Textile substrate with polymer foam coating

ABSTRACT

The present invention relates to a process for preparing composite textile and composite textile obtainable by this process as well as the use of said composite textile for automotive applications among other things. Said process comprises the following steps: (a) applying a foamed polymer dispersion onto a suede-like textile substrate; (b) drying the composite material of polymer foam and substrate; (c) compacting the polymer foam with the substrate; and (d) heat-treating and/or cross-linking the polymer foam. The composite textile is characterised by a suede-like textile substrate and a polymer foam layer.

The present invention relates to a composite textile such as animitation leather with a foam layer, a process for the productionthereof and the use of said composite textile as a cover in automotiveand furniture applications or for garments.

Composite textiles such as imitation leathers or synthetic leathers aregenerally prepared by a process where first a skin or cover layer of apolyurethane resin is formed on a release paper, followed by applicationof an adhesive layer to the polyurethane resin and lamination of thecomposite material thus obtained onto a textile substrate. A“grain-like” structure can be achieved by using uneven release papers.Particularly in case of water-based polyurethane dispersions, however,adhesion between the textile substrate and the polyurethane layer isoften insufficient. In order to solve this problem, EP 1 170 416 A2, forexample, describes the use of a special adhesive composition on apolyurethane basis. DE 42 41 516 C1, on the other hand, teaches needlinga polyurethane foam layer with a non-woven fabric.

In view of this state of the art, it is the object of the presentinvention to provide a new composite textile which is easy to prepareand has good adhesion between the textile substrate and a polymer foamlayer such as a polyurethane foam layer.

It is another object of the present invention to provide a simpleprocess which is suitable for preparing a composite textile such as animitation leather, but especially for preparing imitation grainedleather or imitation Nubuk leather.

On the one hand, these objects of the invention were achieved byproviding a composite textile comprising a suede-like textile substrateand a foam layer and, on the other hand, by providing a process forpreparing a composite textile, comprising the steps of

-   (a) applying a foamed polymer dispersion onto a suede-like textile    substrate;-   (b) drying the composite material of polymer foam and substrate;-   (c) compacting the polymer foam with the substrate; and-   (d) heat-treating and/or cross-linking the polymer foam.

The textile substrate to be used according to the invention has a suedecharacter, i.e. the textile substrate has fibres which, substantially,do not extend in the plane of the textile substrate but stand out in aperpendicular direction (at least 45° in relation to the plane of thetextile substrate) or have a pile. Raised woven fabrics, raisedwarp-knitted fabrics and raised weft-knitted fabrics are preferablyused, raised warp-knitted fabrics being especially preferred.Alternatively, it is possible to use a pile fabric such as pilewarp-knits, pile weft-knits, pile woven materials or Raschel materials.The raised and pile fabrics preferably have a thickness increased by atleast 50%, preferably 70%, vis-a-vis the non-raised material. Forexample, a warp-knitted or weft-knitted material having a thickness of0.5 to 0.8 mm is raised to a thickness of at least 1.0 mm, preferably1.2 to 1.6 mm. In order to obtain an even surface or uniform thicknessafter raising, raising may be followed by a shearing step. It is alsopossible to employ an abrasion step instead of or in addition to theraising step.

Non-woven fabrics may also be used as suede-like textile substratesaccording to the present invention.

The suede-like textile substrates to be used according to the inventionalso include coated textile substrates, e.g. a textile substrate whichhas been coated with a foamed or compacted plastic layer and which wassubsequently treated to obtain the suede character, for example bysueding.

As a rule, the suede-like textile substrate has a thickness of 1 to 2mm, preferably 1.2 to 1.6 mm, especially preferably 1.4 to 1.5 mm.Thickness is determined in accordance with DIN EN 12127.

The suede-like substrate to be used in accordance with the inventionpreferably has a stretch (determined according to DIN 53360) of at least5%, especially preferred 10 to 25%. The indicated stretch relates to thecross-direction, i.e. stretching along the width of the material. In thedirection of the length, stretch is preferably a least 2%, especiallypreferably 5 to 25%.

The yarns used for the textile substrate are not particularly limitedand comprise, among other things, polyester, polyamide and cotton yarns.Polyester yarns are preferred especially for automotive applicationswhile cotton yarns are preferred for garments because they are welltolerated by the skin.

Especially preferred are yarns with fine filaments which preferably havean average count of 2 denier or less, preferably 0.01 to 1.6 denier,especially preferably 0.6 to 1.4 denier.

For example, especially flat or textured polyester yarns with a filamentcount of 0.6 to about 1.4 denier such as flat or textured polyesterfilament yarns (e.g. those textured by a false twisting process) aresuitable.

Micro-split yarns may also be used as yarns for the textile substrate,the micro-fibres preferably having a count of 0.01 to 1 denier.Micro-split yarn of the so-called “sea-island” type is particularlypreferred. The micro-fibres (“islands”) may consist of polyester such aspolyethylene terephthalate or polyamide such as 6 polyamide or 6,6polyamide, while the “sea” or the fibre coat is made of a polymer with asolubility or degradability differing from that of the “island”component, for example polyethylene, polystyrene, polyethyleneterephthalate modified with sodium sulfoisophthalate and polyethyleneglycol. Suitable “sea-island” fibres are described in EP 0 651 090 B1and EP 1 041 191 A2, for example.

The greige textile substrate is preferably pre-dyed with dispersion dyesbefore applying the polyurethane foam. For this purpose, disperse dyesfor hot-lightfast textiles in automotive applications are preferablyused, most preferably the dyes of the TERASIL H® brand made by Ciba andthe dyes of the DOROSPERS® brand made by Dohmen. The light-fastness ofthe disperse dyes used is preferably in the range of these branded dyes.The disperse dye is selected depending on the pigments used, the colourdifference between the disperse dye and the pigment preferably beingsmall or the disperse dye and pigment preferably having the same colourtone. In case of a red colouring, for example, both the disperse dye andthe pigment will be red. This is advantageous, because it helps avoid awhite or grey underground of textile substrate appearing in case oflocal abrasion of the polyurethane layer. The disperse dye is preferablyused in a concentration such that the depth of the colouring with thedisperse dye is less than that of the pigment colouring.

Before coating or applying the foamed polymer dispersion, the textilesubstrate is preferably stretched by 5%, more preferably 10 to 25% andmost preferably 10 to 15%. Stretching is carried out along the width ofthe material, for example from a material width of 1.50 m to one of 1.70m. As a rule, the substrate is wet during this process. For example,stretching may be carried out during drying after the dyeing step withthe disperse dyes with the aid of a tenter frame. In order to achievesufficient stretching, the textile substrate may be heated. Care shouldbe taken to stay below the fixing temperature of the yarn (which isbetween 190 and 215° C. for polyesters and polyamides), since otherwiseshrinkage to the original size during the drying step is no longerguaranteed, i.e. the “memory effect” of the yarn is lost. The preferredtemperature for stretching polyamide or polyester textiles is 100 to160° C., more preferably 140 to 150° C.

The foamed polymer dispersion to be applied onto the textile substrateis not particularly limited and includes a polyurethane dispersion, apoly(vinyl chloride) (PVC) dispersion, as well as dispersion based onpolyacrylates, polystyrene, ethylene-vinyl acetate copolymer, andbutadiene copolymers. A foamed polyurethane dispersion is preferablyused.

In general, a dispersion of a water-based ionomer polyurethane which maycontain a foam stabiliser such as described in WO 94/06852 is used toprepare the foamed polyurethane dispersion. The PU dispersionspreferably have a solid content of 30 to 70 wt.-%, especially 32 to 60wt. %. The term “polyurethane” also includes polyurethane polyureas. Asurvey of polyurethane (PUR) dispersions and processes therefor may befound in Rosthauser & Nachtkamp, “Waterborne Polyurethanes, Advances inUrethane Science and Technology”, vol. 10, pages 121-162 (1987).Suitable dispersions, for example, are also described in“Kunststoffhandbuch”, vol. 7, 2^(nd) ed., Hanser, pages 24 to 26. PURdispersions preferably used in the invention include TUBICOAT PRV®,TUBICOAT MB® (manufacturer/supplier: CHT R. Beitlich GmbH, Tubingen) andthe curable polymer systems described in WO 94/06852.

Known compounds may be used as foam stabilisers, which are preferablycontained in the polymer dispersion during foaming, for examplewater-soluble fatty acid amides, hydrocarbon sulfonates or saponaceouscompounds (fatty acid salts), for example compounds wherein thelipophilic radical contains 12 to 24 carbon atoms; especially alkanesulfonates having 12 to 22 carbon atoms in the hydrocarbon radical,alkyl benzenesulfonates having 14 to 24 carbon atoms in the entirehydrocarbon radical or fatty acid amides or saponaceous fatty acid saltsof fatty acids having 12 to 24 carbon atoms. The water-soluble fattyacid amides are preferably fatty acid amides of mono- ordi-(C₂₋₃-alkanol)amines. For example, the saponaceous fatty acid may bean alkali metal salt, amine salt or unsubstituted ammonium salt. Knowncompounds are generally considered as fatty acids, such as lauric acid,myristic acid, palmitic acid, oleic acid, stearic acid, ricinoleic acid,behenic acid or arachic acid, or technical fatty acids such as coconutfatty acid, tallow fatty acid, soy fatty acid or technical oleic acid aswell as hydrogenation products thereof. Especially preferred areunsubstituted ammonium salts of higher saturated fatty acids, especiallythose having 16 to 24 carbon atoms, primarily stearic acid andhydrogenated tallow fatty acid. The foam stabilisers should be of thekind which decompose neither under foaming conditions nor underapplication conditions. Suitable ammonium salts are those having adecomposition temperature of ≧90° C., preferably ≧100° C. if desired,the more weakly anionic stabilisers (B₁), especially the carboxylicsalts or the amides, may be combined with the more strongly anionicsurfactants (B₂), especially with the above-mentioned sulfonates orpreferably fatty alcohol sulfates, advantageously in the form of saltsthereof (alkali metal or ammonium salts as mentioned above), for exampleat a (B₁)/(B₂) weight ratio in the range of 95/5 to 50/50,advantageously 85/15 to 65/35. The product TUBICOAT STABILISATOR RP®(supplier: CHT R. Beitlich GmbH, Tubingen, Germany) may also be used toadvantage.

If the dispersion contains a foam stabiliser (such as ammoniumstearate), ammonia is preferably added to the dispersion to adjust thepH, preferably in the range of 9 to 11.

In addition, the polymer dispersion usually contains pigments which maybe added both before and after foaming, preferably before foaming.Pigments used in the invention are described in Ullmann's Encyclopediaof Industrial Chemistry, 5.sup.th ed., 1992, vol. A20, pages 243 to 413.The pigments used in the invention may be inorganic or organic pigments,preferably organic pigments. The light-fastness of the pigments usedshould be as high as possible and is preferably in the range of thelight-fastness of the pigments BEZAPRINT®, e.g. BEZAPRINT GELB RR®(yellow), BEZAPRINT GRUN B® (green), BEZAPRINT ROSA BW® (pink),BEZAPRINT BRAUN TT® (brown), BENAPRINT VIOLETT FB® (purple), BENAPRINTROT KGC® (red) and BEZAPRINT BLAU B2G® (blue) (all available from BezemaAG, Montlingen; Switzerland, PIGMATEX GELB (yellow) 2 GNA® (60456),PIGMATEX GLEB (yellow) K® (60455), PIGMATEX FUSHSIA BW® (60416),PIGMATEX MARINE (navy blue) RN® (60434), PIGMATEX BRAUN (brown) R®(60446), PIGMATEX SCHWARZ (black) T® (60402) (all available fromSUNChemical, Bad Honnet Germany); OCTER (ochre) E. M. B.® (Ref. 3500),ROT-VIOLETT (red-purple) E. M. B.® (Ref. 4406), BRAUN (brown) E. M. B.®(Ref. 5550) and BLAU (blue) E. M. B.® (Ref. 6500) (all available fromRMB NR, Bronheim, Belgium) which are particularly preferred in theinvention. The light-fastness values are preferably at least 6, morepreferably at least 7 (blue scale; 1 g/kg, see DIN 75 202). the amountof pigments used depends on the intended depth of the colour and is notparticularly limited. Preferably, the pigment is used in an amount of upto 10 wt.-% based on the total weight of the polymer dispersion(preferably a PU dispersion), especially preferably in an amount of 0.1to 5 wt.-%.

The dispersion used for the polymer foam preferably also contains afixing agent.

Fixing agents preferred for the PU foam to be used according to theinvention are aminoplasts or phenolic resins. Suitable aminoplasts orphenolic resins are the well-known commercial products (cf. “UllmannsEnzyklopädie der technischen Chemie”, vol. 7, 4^(th) edition, 1974,pages 403 to 422, and “Ullmann's Encyclopedia of Industrial Chemistry,vol. A19, 5^(th) ed., 1991, pages 371 to 384.

The melamine-formaldehyde resins are preferred, replacement of 20 mol-%of the melamine with equivalent amounts of urea being possible.Methylolated melamine is preferred, for example bi-, tri- and/ortetramethylol melamine.

The melamine-formaldehyde resins are generally used in powder form or inthe form of their concentrated aqueous solutions which have a solidscontent of 40 to 70 wt. %. For example, TUBICOAT FIXIERER HT® (availablefrom CHT R. Beitlich GmbH, Tubingen) may be used.

Alternatively, fixing agents may be aliphatic or aromatic isocyanates,which may optionally be blocked, as well as polyaziridine.

The dispersion used for the polymer foam preferably also contains aflame retardent.

Suitable flame retardants are antimony trioxide Sb₂O₃, antimonypentoxide Sb₂O₅, alumina hydrate Al₂O₃.3H₂O, zinc borate Zn(BO₂)₂.2H₂Oor 2ZnO.(B₂O₃)₃.(H₂O)_(3,5), ammonium ortho- or polyphosphate NH₄H₂PO₄or (NH₄PO₃)_(n) and chloroparaffines.

Especially preferred are the phosphonic acid esters, particularly5-ethyl-2-methyl-1,3,2-dioxaphosphorinane-5-yl)methylphosphonate-P-oxide andbis(5-ethyl-2-methyl-1,3,2-dioxaphosphorinane-5-yl)methyl methylphosphonate-P,P′-dioxide, decabromodiphenylether, hexabromocyclodecaneand polyphosphonates such as the product APIROL PP 46® of CHT R.Beitlich GmbH, Tubingen, which is preferably used in an amount of 150 to250 parts, especially preferably 170 to 190 parts per 1000 parts of thetotal dispersion.

The polymer dispersion used according to the invention may also containplasticisers, thickening agents, emulsifiers and/or sun-screens.

Suitable plasticisers are the substances listed in A. K. Doolittle, “TheTechnology of Solvents and Plasticizers”, J. Wiley & Sons. Ltd. Polymerplasticisers are preferably used, for example TUBICOAT MV® (availablefrom CHT R. Beitlich GmbH, Tubingen) and MILLITEX PD-92® (Milliken,U.S.A.). The amount of plasticiser should be as low as possible in orderto ensure good abrasion resistance of the final product. The plasticiseris preferably used in an amount of up to 10 wt. % based on the totalweight of the composition, more preferably 2 to 7 wt. %.

Suitable thickening agents are common thickening agents such aspolyacrylic acids, polyvinyl pyrrolidones or cellulose derivatives suchas methyl cellulose or hydroxy ethyl cellulose, e.g. TUBICOAT HEC®(available from CHT R. Beitlich GmbH, Tubingen).

As emulsifiers, the composition used in the invention may contain alkylsulfates, alkyl benzene sulfonates, dialkyl sulfosuccinates,polyoxyethylene alkyl phenyl ether, polyoxyethylene acyl ester and alkylaryl polyglycol ether such as TUBICOAT EMULGATOR HF® (available from CHTR. Beitlich GmbH, Tubingen) or fatty acid salts in the form of theiralkali or ammonium salts.

Sunscreens such as bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate andmethyl-1,2,2,6,6-pentamethyl-4-piperidyl sebacate, UV absorbers andsterically hindered phenols may also be included in the composition usedaccording to the invention.

Before application to the textile substrate, the polymer dispersion(e.g. the polyurethane dispersion) is foamed, usually by a mechanicalprocess. This may be carried out in a foam mixing device withapplication of high shear forces. Foaming in a foam generator by blowingin pressurised air is another alternative. A Stork mixer or a foamprocessor, e.g. the STORK FP3® foam processor, is preferably used.Foaming is carried out in such a manner that the foam density obtainedis preferably 150 to 280 g/l, especially preferably 180 to 220 g/l.

The foam thus obtained is stable, i.e. it does not decompose into aliquid after application, but remains on the textile substrate in thefoamed form.

The coating step with the stable foam is carried out using a foamapplication system by a knife-over-roll coater, an air squeegee,Variopress or, preferably, an open doctor blade with a pressure template(STORK Rotary Screen Coating Unit CFT®). The thickness of the foam afterapplication is usually between 0.4 and 0.8 mm, preferably 0.5 to 0.6 mm.

The composite material of polymer foam and substrate thus obtained isthen dried, usually at 80 to 150° C., preferably 100 to 130° C. If thetextile substrate has been stretched before application of the polymerfoam, it is preferred to carry out the drying step on an aggregatepermitting free shrinkage of the composite material of foam andsubstrate, for example a suspended loop drier or a belt drier (bratticedrier).

If the textile substrate has been stretched before application anddrying permits free shrinkage of the substrate, said shrinkage processproduces a grain-like structure and therefore an imitation leather witha grain-like or Nubuk appearance. If the material was not stretched, asmooth imitation leather is produced. The strength of the grainingdepends on the pile of the textile substrate: The higher the pile, thestronger the graining; the denser the pile, the finer the graining.

Therefore, the invention provides a process for preparing a grain-typeor Nubuk imitation leather which is much simplified in comparison withthe common process for preparing a Nubuk leather which comprises atransfer coating from an embossed release paper. In addition, the grainor Nubuk leather imitations obtained by the process of the inventiondiffer from grain-type imitation leather of the prior art insofar as thegrains have no repeat pattern (repetition of the grain structure atcertain intervals) which is obtained in prior art processes by using anembossing roll.

After that, the polymer foam is compacted with the substrate under highpressure. Such compacting may be carried out on a pressing machine suchas a calender in a temperature range of 20 to 180degree. C., preferably100 to 180.degree. C. and a line pressure of 10 to 60 t (or up to 6bar), or on a fixing machine such as SUPERCRAB GCP® 1200 (m-tecMaschinenbaugesellschaft mbH, Viersen) at 100 to 160° C., preferably 135to 140° C. and pressures of 10 to 200 bar, preferably 120 to 180 bar. Bythis action, foam is compressed (e.g. from a foam thickness of 0.6 mm to0.2 to 0.4 mm) and adhesion between the foam and the textile substrateensured.

The use of a fixing machine such as SUPERCRAB GCP® provides acomparatively long contact time of a few seconds (usually 3 to 5seconds) so as to transfer sufficient heat to the composite material sothat part of the polymer foam is heat-treated already so that theprocess steps of compaction and heat-treatment may be combined.

If sufficient heat-treatment is not achieved during the compacting step,the composite material is heated subsequently, preferably to effect across-linking or gelation of the foam, e.g. to a temperature sufficientto ensure adequate condensation of the PU foams or a gelation of the PVCfoam, e.g. 140 to 180° C., preferably 170 to 180° C. Such heat-treatmentmay take place on a tenter frame so that the material is tentered andbrought to its final width at the same time. Alternatively, theheat-treatment may be carried out while the composite material issubjected to a mechanical treatment, e.g. in a tumbler.

The process steps (a) to (c) (foam application; drying; compacting) maybe repeated. This is preferred in these cases where the first foamcoating does not completely cover the surface of the textile substrate,e.g. when coating open-meshed fabrics or non-wovens.

After compaction, the surface may be finished by applying a lacquer ortop coating. The lacquer may be based on polyacrylates or PVC. However,a PU coating is particularly preferred, especially for coating PU foams.

A PU top coating applied to a PU foam is especially preferred in caseswhere the composite textile has to meet high mechanical requirements,for example for use in automotive applications. On the other hand, thetop coating reduces the vapour permeability of the composite material ofpolyurethane foam and substrate which is usually good. Said top coatingmay be applied in an immersion process (e.g. at a liquor pick-up of 40%)as a meta-stable foam or by means of an air squeegee, foam applicationbeing especially preferred with a view to breathing properties andvapour permeability, because a top coating applied in this matterreduces vapour permeability only to a negligible extent.

As a rule, the PU dispersion for the top coating is a water-based PUdispersion which essentially corresponds to the PU dispersion for the PUfoam, but does not contain a foam stabiliser. The dry content of the PUdispersion used is preferably 30 to 60 wt. %, especially 32 to 50 wt. %.In comparison with the PU dispersion for the foam layer, the PUdispersion for the top coating is harder, i.e. the polyurethane has alower content of soft segments (see Ullmann's Encyclopedia of IndustrialChemistry, 5.sup.th ed., 1992, vol. A20, pages 674 to 677). Use of thePU dispersion TUBICOAT PUH® by CHT R. Beitlich GmbH, Tubingen (solidscontent 40%) is preferred.

If the PU dispersion is applied as a meta-stable foam, it preferablycontains the same thickeners as indicated for the PU foam, ammoniaand/or a fixing agent as well as a foaming agent. Said foaming agent isusually a surfactant, preferably a non-ionic surfactant such as alkylamine oxide or an anionic surfactant such as ammonium stearate, forexample the foaming agent TUBICOAT AOS® by CHT R. Beitlich GmbH,Tubingen. Before application, the dispersion is foamed to foam weightsof 50 to 400 g/l, preferably 50 to 250 g/l.

If the PU dispersion is applied with the aid of an air squeegee, itpreferably contains a defoaming agent such as TUBICOAT ENTSCHUMER N® byCHT R. Beitlich GmbH instead of the foaming agent.

If the PU dispersion is applied by an immersion process, it preferablydoes not contain a foaming agent, but may contain a defoaming agent ifthe dispersion has the tendency to foam.

In order to improve light-fastness, it may be advantageous toincorporate a sunscreen into the PU dispersion for the top coating.

After application of the top coating, the composite material ispreferably dried in a tenter frame at a temperature of 140 to 190° C.,more preferably 170 to 180° C. Crosslinking takes place during thisdrying step.

After that, the composite material is preferably subjected to mechanicaltreatment in a tumbler which makes the material softer and any grainpattern present more pronounced. This treatment is preferably carriedout at an excess pressure of up to 6 bar, preferably a pressure of 3 to4 bar, and elevated temperatures, preferably 110 to 160° C. In addition,it is preferred to conduct such treatment under a defined humidity, e.g.3 to 10%.

After that, a tentering and drying step may be carried out on acommercial tenter frame.

The invention also comprises a composite textile obtainable by theprocess described above.

The composite textile of the invention—which may have the appearance andfeel of leather, i.e. is an imitation leather—is characterised by asuede-like textile substrate and a polymer foam layer, preferably apolyurethane foam layer. The thickness of the composite textile isusually 1 to 2 mm, which essentially corresponds to the thickness of thesuede-like textile substrate (thickness of the textile substratepreferably 1 to 1.8 mm). As discussed above, the composite textile isalso characterised by the fact that any grains present do not have arepeat pattern. This is in contrast to known grained leathers which havea repeat pattern defined by the circumference of the embossing roll usedin the embossing process. The maximum repeat pattern of known grainedleather is about 1 m.

The composite textile, (e.g. imitation leather) of the invention isparticularly well suited for internal automotive applications, toexample for dashboards, side-panel liners, rear shelves, roof liners,boot liners and seats as well as for the production of upholsteredfurniture, especially as covers for easy chairs, couches and chairs. Inaddition, it is suitable for garments (especially outer garments) andfor use in the shoe industry as top material and lining.

EXAMPLE

Starting material: 3-bar warp-knitted fabric Guide bar 1: 45f32T-611flat, 33.4% Guide bar 2: 45f32T-611 flat, 45.7% (alternatively, 83f136with micrell texture Guide bar 3: 50f20T-610 flat 20.9%

All yarns are greige yarns, i.e. of an untreated white colour.

Path of treatment:

-   1. Pre-sueding on several tambours-   2. Sueding and shearing-   3. Dyeing with selected disperse dyes as formulated-   4. Drying

The textile substrate is now ready for coating (weight per unit area 250g/m²).

After dyeing, the substrate is dried at 150° C. with the aid of a tenterframe and stretched (by 10% of the subsequent width of the material).

As a next step, the pre-dyed material is coated with the followingpre-foamed PU dispersion (in wt.-%):

TUBICOAT PRV ®  950 parts CHT, Tübingen TUBICOAT FIXING AGENT   50 partsCHT, Tübingen H.T. ® TUBICOAT   5 parts CHT, Tübingen STABILISATOR RP ®Ammonia (25%)   3 parts Any product suitable APIROL PP46 ®  180 partsCHT, Tübingen BEZAPRINT SCHWARZ   40 parts Bezema, CH- DW ® MontlingenBEZAPRINT BLAU BT ®   5 parts Bezema, CH- Montlingen BEZAPRINT ROSA BW ® 0.5 parts Bezema, CH- Montlingen

Viscosity (Haake, VT02) 15 20 dPas (25° C.), pH value 9 to 10.

The coating process with a stable foam is carried out using a foamprocessor and a foam application system with an open doctor blade with apressure template (STORK Rotary Screen Coating UNIT CFT®).

After that drying was carried out at 100 to 110° C. in a belt dryer in afirst field at 110° C., a second field at 120° C. and then a third fieldat 130° C.

In the next process step, the material is simultaneously exposed to ahigh pressure and a high temperature on a SUPERCRAB GCP® 1200 (m-tecGmbH) at 140° C. (right-hand side against silicone rolls) and a pressureof 150 bar in order to compact the substrate and the PU.

Tentering and condensing is carried out on a tenter frame at 175° C. andthe material brought to its final width.

Three different top coatings were alternatively applied to the compositematerial of polyurethane foam and substrate:

-   a) Top coating by an immersion process: 100 to 300 g/l TUBICOAT PUH®    plus 2% TUBICOAT fixing agent HT® via foulard are applied (liquor    pick-up 40%).-   b) Top coating by foam application: the following dispersion was    foamed to 50 to 250 g/l and then applied with a foam applicator    (parts by weight):

TUBICOAT PUH ®  950 parts CHT, Tübingen TUBICOAT  1.5 parts CHT,Tübingen THICKENING AGENT HEC ® Ammonia (25%)   3 parts Any productsuitable TUBICOAT AOS ®   40 parts CHT, Tübingen TUBICOAT FIXING   20parts CHT, Tübingen AGENT H.T. ®

-   c) Top coating via an air squeegee: The following dispersion was    applied with the aid of an air squeegee (parts by weight):

TUBICOAT PUH ® 950 parts CHT, Tübingen Tubicoat defoaming  5 parts CHT,Tübingen agent TUBICOAT FIXING  10 parts Any product AGENT H.T. ®suitable TUBICOAT  20 parts CHT, Tübingen THICKENING AGENT LP ®

-   -   Drying and condensation is then carried out on a tenter frame at        175° C. followed by processing in a tumbler (Thies, Coesfeld)        under a pressure of 3 to 4 bar and approx. 6% humidity, 140° C.        and 600 rpm.    -   The process is completed by a tentering and drying process on a        commercial tenter frame.    -   Laboratory results achieved:    -   X1200 exposure test (Ford method, FLTMBO 150-02): Grade 4    -   Abrasion Resistance:    -   The sample material passed the test with an intact coating up to        60,000 Martindale abrasion cycles.

1. A process for preparing a polyurethane-containing composite textileof imitation leather, the process comprising the steps of; (a) providinga knitted or woven textile substrate having a length and a width; (b)stretching the knitted or woven textile substrate along its width, thetextile substrate having fibers which do not extend in the plane of thetextile substrate but stand out at least 45° in relation to said plane,or having a pile, said stretching being effective to increase the widthdimension of said substrate by at least 5%; (c) applying a foamedpolyurethane dispersion onto the textile substrate to form a compositematerial; (d) drying the composite material, thereby facilitating freeshrinkage of the composite material; (e) compacting the compositematerial; and (f) condensing the composite material.
 2. A processaccording to claim 1, comprising the additional step of applying apolyurethane top coating to the composite material following thecompacting step (e).
 3. A process according to claim 1, wherein thetextile substrate has a thickness of at least 1 mm.
 4. A processaccording to claim 1, wherein the textile substrate is a warp-knittedfabric.
 5. A process according to claim 1, wherein the textile substrateis pre-dyed with disperse dyestuffs.
 6. A process according to claim 1,wherein the foamed polyurethane dispersion contains pigment duringapplication.
 7. A process according to claim 1, comprising theadditional steps of: (g) providing a tumble process followingcondensation; and (h) applying a top coating or lacquer.
 8. A processaccording to claim 1, wherein an application of a top coating is placedupon the composite material following the step of condensing thecomposite material.
 9. A process according to claim 8, wherein the topcoating is a lacquer.
 10. The process according to claim 8, wherein thetop coating is a polyurethane.
 11. The process according to claim 8,wherein the composite is dried on a tenter after the application of atop coating.
 12. The process according to claim 7, wherein the tumbleprocess comprises mechanical treatment in a tumbler.